INVESTMENTS (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) security	Mar. 31, 2016 USD ($)	Dec. 31, 2016 security
INVESTMENTS [Abstract]
Proceeds from sales of available-for-sale investment securities	$ 111.5	$ 66.7
Debt and equity securities held in an unrealized loss position | security	573		1,132
Debt securities and equity securities held in an unrealized loss position 12 months or more | security	23		36
OTTI losses	$ 0.0	$ 0.0
Fair value of investments deposited with governmental authorities required by law	$ 10.6